Sql Server Mystery Slow Delete In Sql Table Stack Overflow

Sql Server Mystery Slow Delete In Sql Table Stack Overflow I've deleted all triggers, foreign keys, constraints, and indexes from the original table. deleting a row from the stripped down table still takes around 1000 ms on average. After upgrading from sql server from 2012 to 2019 we have encountered problems with very simple delete query like: delete [ sales].[offerdetail] where [offerdetailsid]=@1 operation takes about 15 30 seconds. when analyzing query plan there are nonclustered index scan, table spool and hash match operations that takes most of the time.

Sql Server Mystery Slow Delete In Sql Table Stack Overflow Unfortunately, there isn’t a quick answer to this, as several factors could be contributing to the delay. let’s explore two of the most common causes i’ve encountered. for this example, i’m using brent ozar’s version of the stack overflow 2010 10gb database. is something blocking my delete? sql server has a feature called blocking. Sqlserver is not optimized for large deletes. generally you can improve performance by deleting in smaller batches (1k to 10k). also if you have cascading deletes, do them first. check if exists deadlocks or blocking. if the table you delete from is referenced by other tables, make sure those other tables have indexes on the foreign key column (s). If the table you are deleting from has before after delete triggers, something in there could be causing your delay. additionally, if you have foreign keys referencing that table, additional updates or deletes may be occurring. It seems likely the very large ntext data is highly fragmented, causing a large amount of random i o (or other inefficiencies) when locating lob fragments to delete.

Sql Server Mystery Slow Delete In Sql Table Stack Overflow If the table you are deleting from has before after delete triggers, something in there could be causing your delay. additionally, if you have foreign keys referencing that table, additional updates or deletes may be occurring. It seems likely the very large ntext data is highly fragmented, causing a large amount of random i o (or other inefficiencies) when locating lob fragments to delete. We are running a delete statement on database every weekend where it deletes rows based on the 16 where conditions. it has to pass 16 where conditions before delete more than millions row. When i execute now a delete of 1 record, the execution time is above 60secs. the statement i execute is a direct delete from tblas0002 where id=2218801. see execution plan below in a public link. looking into the execution plan, i can see only one operation taking over 1 minute, and it is a scan of the primary key index of the tblas0002. but why?. In this article, we explored the complexities of the sql delete operation and why they can be unexpectedly slow. we examined the internal working process of the delete statement, including transaction logging, locking mechanisms, and foreign key constraint checks. When we delete 10,000s of rows from these shallow tables the delete queries are generally quite fast (at most a handful of seconds). we also have a table with a field of type image storing images averaging 100 kb. when we delete only a few thousand rows from this table, it takes well over a minute.

Sql Server Mystery Slow Delete In Sql Table Stack Overflow We are running a delete statement on database every weekend where it deletes rows based on the 16 where conditions. it has to pass 16 where conditions before delete more than millions row. When i execute now a delete of 1 record, the execution time is above 60secs. the statement i execute is a direct delete from tblas0002 where id=2218801. see execution plan below in a public link. looking into the execution plan, i can see only one operation taking over 1 minute, and it is a scan of the primary key index of the tblas0002. but why?. In this article, we explored the complexities of the sql delete operation and why they can be unexpectedly slow. we examined the internal working process of the delete statement, including transaction logging, locking mechanisms, and foreign key constraint checks. When we delete 10,000s of rows from these shallow tables the delete queries are generally quite fast (at most a handful of seconds). we also have a table with a field of type image storing images averaging 100 kb. when we delete only a few thousand rows from this table, it takes well over a minute.